http://news.bbc.co.uk/1/hi/uk/8633892.stm

Thankfully the Wench has now made it back. Was able for fly from Lusaka to Heathrow, stopping to refuel in Barcelona, but only as a "just in case" they were diverted.

So the party is cancelled then?

I know the ban has been lifted as they've decided that it is safe to fly through certain concentrations of ash but I'd be curious as to what the effects will be of a plane making multiple flights through ash, whether there may be a cumulative issue.

Maybe the bookies will be taking bets on plane crashes in Europe? I should have a look on Betfair.

I gather they will be inspecting the engines after each flight although I'm not sure if this is going to be an enforced requirement or something optional.

Plus BA, and possibly other airlines, have indicated they are seeking compensation from the government and/or the EU because of the closure of air space.
Thing is, I bet they'd be the first to blame NATS (or possibly the Met Office) if their planes were plummeting out of the air

I doubt that any airline has the resources to check the engines after every flight. They certainly can not afford spare engines to do this. They might have a few spares over an entire fleet but not per aircraft while they inspect them They certainly will not have the time to do a proper inspection in the 90 minutes turnaround that they have at some airports and some airlines run with turnaround of 20 minutes or so. Though if they can analyse the fuel consumption whilst on the ground in static test they could find out how much damage has actually been done.

While they might sue the government for losses they may not have much chance because the rules were in place before the incident, and they did not protest before. Also if they had flown and there had been an incident their insurers would have walked away from liability and the airline would have collapsed from a single crash. The case against the government is weak because the aircraft manufacturers recommend grounding during ash clouds and all the other governments in the affected zones did so as well.